Original article Biliopancreatic diversion: long-term effects on gonadal function in severely obese men Sergio Alagna, M.D. a, *, Maria L. Cossu, M.D. b , Paola Gallo, M.D. a , Pier L. Tilocca, M.D. b , Piera Pileri, M.D. a , Giuliano Alagna, M.D. a , Paola Maninchedda, M.D. a , Annalisa L. Sini, M.D. a , Luca Pilo, M.D. b , Pier P. Rovasio, M.D. a , Giuseppe Noya, M.D. c , Antonia Masala, M.D. a a Department of Internal Medicine, Institute of Medical Pathology, University of Sassari, Sassari, Italy b Department of General Surgery, Section for Severe Obesity and Related Pathology, University of Sassari, Sassari, Italy c Department of Surgery Sciences, University of Perugia, Perugia, Italy Manuscript received May 3, 2005; revised January 12, 2006; accepted January 13, 2006 Abstract Background: This study investigated hormonal parameters of gonadal function in severely obese men before and 1 year after undergoing biliopancreatic diversion (BPD). Methods: This observational 1-year postoperative study conducted at medical and surgical clinics at an academic medical center in Italy followed 20 severely obese men age 21 to 63 years, with a mean ( standard deviation) body mass index (BMI) of 47.3  13.1. The following parameters were evaluated: body composition, using body impedance analysis (BIA), and serum levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), total testosterone, estradiol 17, and leptin. Results: At a mean 12  1 months after surgery, the patients showed a significant decrease in weight, from 132.1  36.9 before surgery to 93.5  20 kg (P  .0001), and BMI, from 47.3  13.1 before surgery to 33.5  7(P  .0001). LH increased from 2.42  1.59 to 4.97  2.6 mIU/ml (P  .0001), FSH increased from 2.85  1.85 to 4.9  4.2 mIU/mL (P = .021), and total testosterone increased from subnormal presurgical values to within normal range (2.81  1.08 to 9.12  1.37 ng/mL; P  .0001), whereas estradiol 17 decreased from elevated basal levels of 44.0  29 to 16.7  6.9 pg/mL (P  .0001). The basal leptin level dropped from 33.0  9.23 to 16.6  5.12 ng/mL (P  .0001), reflecting the decrease in body fat. Subjective improvement in sexual performance was reported by 80% of patients. Conclusions: Severe obesity is coupled with some significant alterations of the gonadotropin- testicular axis and estradiol 17 and leptin blood levels. These derangements were substantially corrected by 1 year after BPD. © 2006 American Society for Bariatric Surgery. All rights reserved. Keywords: Biliopancreatic diversion; Gonadotropins; Testosterone; Estradiol 17; Leptin Obesity is associated with various endocrine alterations in both sexes [1]. Several observations suggest the existence of significant changes in blood levels of gonadal steroid hormones in obese men, including decreased total testoster- one [2–7] and free testosterone [8,9] (although the latter finding is equivocal), proportional to the amount of body fat present [6]. The pathogenic mechanisms of these endocrine modifications have not been completely defined. An in- creased peripheral conversion of androgens to estrogens [9,10] and a significantly reduced binding between serum testosterone and the carrier protein sex hormone– binding globulin (SHBG) have been reported in the literature [2]. Some data point to the existence of a central mechanism *Reprint requests: Sergio Alagna, M.D., Department of Internal Med- icine, Institute of Medical Pathology, University of Sassari, Viale San Pietro 8, 07100 Sassari, Italy. E-mail: sealagn@tin.it Surgery for Obesity and Related Diseases 2 (2006) 82– 86 1550-7289/06/$ – see front matter © 2006 American Society for Bariatric Surgery. All rights reserved. doi:10.1016/j.soard.2006.01.005